Kaspar's lab previously determined that this particular viral vector can cross the blood-brain barrier, a characteristic that is required to ensure this protein reaches nerve cells in the spinal cord.
The research group demonstrated that effect in this study, as well, by intravenously injecting some of the disease-model mice with a green fluorescent protein that functioned as a marker of where the virus traveled in the body. Ten days after the injection, 42 percent of spinal motor neurons in these mice showed that they contained the fluorescent protein.
Similarly, mice with spinal muscular atrophy that received the SMN protein via the viral vector when they were 1 day old showed increases of the protein in the brain, spinal cord and muscles within 10 days, though the levels remained lower than the levels of SMN in normal mice.
Those higher levels of the protein appeared to be sufficient to reverse effects of the disease, Burghes said. That is significant because, based on mouse data, the disease is believed to affect people with SMN levels below about 20 percent of normal. But people with only 50 percent of the expected amount of the protein in their motor neurons do not have the disorder.
In addition, a single gene therapy treatment appears to reverse the disease, as opposed to drug treatments under investigation that might elevate SMN protein levels but would require a lifetime of taking medication.
In this study, the researchers tested mice with SMA after the treatment with the protein for their ability to roll the
|Contact: Arthur Burghes|
Ohio State University